1. Field
The described technology relates generally to a thin film transistor. More particularly, the described technology relates generally to a thin film transistor including polycrystalline semiconductor layers, a method of manufacturing the active layers of the thin film transistor, and a display device including the thin film transistor.
2. Description of the Related Art
A display device is used to display an image. An organic light emitting diode (OLED) display has been increasingly used as the display device. The organic light emitting diode (OLED) display is self-light emitting and can reduce a thickness and a weight of the display device because it does not require an additional light source, as is used in a liquid crystal display (LCD). Further, the organic light emitting diode (OLED) display has high quality characteristics, such as low power consumption, high luminance, and a high response speed. A conventional organic light emitting diode (OLED) display includes a thin film transistor (TFT) formed in each pixel of the OLED display and an organic light emitting element connected to the thin film transistor.
The thin film transistor includes a semiconductor layer. Recently, a technique for forming a silicon layer using a polycrystalline semiconductor layer through the diffusion of a metal catalyst has been developed. However, in a case in which the silicon layer is formed of a polycrystalline semiconductor layer through the diffusion of the metal catalyst, a concentration of the metal catalyst at a portion where the diffusion of the metal catalyst is ended is higher than a concentration at other portions. Accordingly, there is a problem in that a semiconductor characteristic of the polycrystalline semiconductor layer deteriorates.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.